1. Field of the Invention
The invention relates to a chain store and a process for loading the chain store.
The chain store and the process can be used for the temporary storage of articles or products of the same type.
The articles or products may be, for example, chocolate bars which are transported from a production apparatus to at least one packaging apparatus. However, the products may consist not of chocolate bars but of other sweet or nonsweet food in the form of pieces, for example bakery articles, or of cans or other containers having any filling or of components for mechanical engineering, for example ball bearings, which are transported to a packaging apparatus or other processing apparatuses.
2. Description of the Prior Art
In the case of known means for the production and packaging of chocolate bars, the bars produced by a production apparatus are transported via a feed belt to a chain store and then through this to packaging apparatuses. The chain store serves in this case as a compensating apparatus for compensating variations in the feed rate of bars or the packing rate of the packaging apparatus and complete stoppages of operation of the production apparatus or of the packaging apparatus, for example lasting for 5 min to 45 min. A chain store of this type typically has 150 to about 1200 gondolas attached to two continuous chains and having a plurality of shelves for holding one row of bars each. Each chain is deflected by a plurality of chain wheels mounted in a frame and by a plurality of chain wheels mounted on vertically displaceable carriages and forms a number of loops.
In the case of the known chain stores, those chains for the loading and unloading side which are each driven by a drive motor are intermittently moved, i.e. they are stationary while products are being loaded onto the shelves at the loading station and are being unloaded again on the shelves at the unloading station. The store operates according to the xe2x80x9cfirst-inxe2x80x9d/xe2x80x9cfirst-outxe2x80x9d principle and makes it possible to operate infeed and outflow at different speeds.
Thus, one storage level after the other is loaded for filling the chain store, for which purpose a loading motor controlled by a control mechanism moves the loading side stepwise past the loading station, while the unloading side controllable by an unloading motor is blocked. For removal of articles from the store, the unloading side is moved stepwise past the unloading station so that the storage levels can likewise be unloaded stepwise.
Because of the requirement for realizing constantly higher capacities and for increasing in particular the loading frequency of the store, the gondolas rock to an increasing extent at the deflection pulleys. This can lead to rocking of the gondolas over the total length of the chain at a sufficiently high cycle frequency or transport velocity, which in the extreme case results in the goods being thrown out of the gondolas.
This disadvantage has long been known to a person skilled in the art. Thus, for example, U.S. Pat. No. 4,813,752 discloses an antioscillation system which, by rolling of gear wheels in the manner of a planetary gear, ensures that the gondolas are guided perpendicularly and rigidly in the region of the deflection pulleys, in order thus to avoid disadvantageous rocking movements. Said system comprises gear wheels which are arranged on the deflection pulleys and the gondolas and engage one another with their teeth during the deflection.
This antioscillation system has the disadvantage that the gondolas are guided at the deflection pulleys so rigidly that the goods present on the storage level may be thrown off owing to the centrifugal force acting only on them in this casexe2x80x94and no longer on the gondolasxe2x80x94and produced by the deflection, if the velocity at which the gondolas are guided around the deflection pulleys exceeds a limit dependent on the mass of the goods.
It is the object of the invention to propose a chain store by means of which the above-mentioned disadvantage can be at least partly avoided, so that in particular the loading frequency can be increased compared with the conventional chain store.
This object is achieved, according to the invention, by a chain store comprising two continuous chains which together carry gondolas serving for holding goods and are driven together by gear wheels or chain wheels rigidly connected to one another, each chain being guided by means of upper and lower stationary deflection pulleys, on the one hand a loading station and on the other hand an unloading station being provided on the two outermost sides of the chain, and one drive device each being coordinated with the loading and unloading side, which device in each case drives the lower or upper stationary outermost deflection pulley coordinated with the loading or unloading side, wherein
each chain is guided in the region of the loading station around two stationary deflection pulleys and over two deflection pulleys, each of which is mounted freely rotatably in a vertically displaceable carriage, in such a way that the chain passes in each case from the outermost, upper or lower deflection pulley mounted freely rotatably in the first carriage downwards or upwards, respectively, to a further stationary deflection pulley and from there perpendicularly upwards or downwards, respectively, to the next upper or lower deflection pulley mounted in a stationary manner, that it passes in each case from the second outermost lower or upper stationary deflection pulley perpendicularly upwards or downwards, respectively, to the deflection pulley of the second carriage and from there perpendicularly downwards or upwards, respectively, to the lower or upper outermost deflection pulley mounted in a stationary manner,
the two carriages are arranged one on top of the other in a staggered manner and are additionally connected to one another by means of at least one chain, one belt or one tackle, which chain, belt or tackle is guided around an upper deflection pulley mounted in a stationary manner, and
a drive device is provided for separating the movement of the chain during loading into a chain movement which has a high frequency in the region of the loading side and an adjacent continuous or low-frequency chain movement.
A further object of the invention is a process for controlling a chain store as mentioned above, wherein the drive device has a compensating motor which drives the chain or uncouples from it in such a way that the movement of the chain during the loading is separated into a high-frequency chain movement in the region of the loading side and into a continuous or low-frequency chain movement in the remaining chain region, so that disadvantageous rocking of the gondolas during the high-frequency loading process over the total length of the chain is thus prevented.